<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <title></title>
    <style>
        #graph {
/*            border: 1px solid black;
            height: 100%;
            width: 100%;
            box-sizing: border-box;*/
        }
    </style>
</head>
<body>
<div id="circle" style="width: 500px;float: left;"></div>
</body>
</html>
<script type="text/javascript">
(function(window,undefined){
    var data = [
        {"product":"产品1","sales":[192.44 ,210.54 ,220.84 ,230.11 ,220.85 ,210.59 ,205.49 ,200.55 ,195.71 ,187.46 ,180.66 ,170.90]},
        {"product":"产品2","sales":[122.41 ,133.16 ,145.65 ,158.00 ,164.84 ,178.62 ,185.70 ,190.13 ,195.53 ,198.88 ,204.32 ,210.91]},
        {"product":"产品3","sales":[170.30 ,175.00 ,170.79 ,165.10 ,165.62 ,160.92 ,155.92 ,145.77 ,145.17 ,140.27 ,135.99 ,130.33]},
        {"product":"产品4","sales":[165.64 ,170.15 ,175.10 ,185.32 ,190.90 ,190.01 ,187.05 ,183.74 ,177.24 ,181.90 ,179.54 ,175.98]}
    ]
        
    var dom_circle = document.getElementById('circle');
    if(dom_circle != undefined && dom_circle != null)
    {
        var canvas = document.createElement("canvas");
        dom_circle.appendChild(canvas);
        var ctx = canvas.getContext('2d');
        var defaultStyle = function(Dom,canvas){
            if(Dom.clientWidth <= 300)
            {
                canvas.width = 300;
                Dom.style.overflowX = "auto";
            }
            else{
                canvas.width = Dom.clientWidth;
            }
            if(Dom.clientHeight <= 300)
            {
                canvas.height = 300;
                Dom.style.overflowY = "auto";
            }
            else
            {
                canvas.height = Dom.clientHeight;
            }
            //坐标轴区域
            //注意，实际画折线图区域还要比这个略小一点
            return {
                p1:'green',
                p2:'red',
                p3:'yellow',
                p4:'purple',
                x: 0 ,    //坐标轴在canvas上的left坐标
                y: 0 ,    //坐标轴在canvas上的top坐标
                maxX: canvas.width ,   //坐标轴在canvas上的right坐标
                maxY: canvas.height ,   //坐标轴在canvas上的bottom坐标
                r:(canvas.width)/2,  //起点
                ry:(canvas.height)/2,  //起点
                cr: (canvas.width)/4, //半径
                startAngle:-(1/2*Math.PI),               //开始角度
                endAngle:(-(1/2*Math.PI)+2*Math.PI),     //结束角度
                xAngle:1*(Math.PI/180)                   //偏移量
            };
        }
        //画圆
        var tmpAngle = -(1/2*Math.PI);
        var ds = null;
        var sum = data[0]['sales'][0]+data[0]['sales'][1]+data[0]['sales'][2]+data[0]['sales'][3]
        var percent1 = data[0]['sales'][0]/sum * Math.PI * 2 ;
        var percent2 = data[0]['sales'][1]/sum * Math.PI * 2 + percent1;
        var percent3 = data[0]['sales'][2]/sum * Math.PI * 2 + percent2;
        var percent4 = data[0]['sales'][3]/sum * Math.PI * 2 + percent3;
        console.log(percent1);
        console.log(percent2);
        console.log(percent3);
        console.log(percent4);
        var tmpSum = 0;
        var drawCircle = function(){
            
            
            if(tmpAngle >= ds.endAngle)
            {
                return false;
            }
            else if(tmpAngle+ ds.xAngle > ds.endAngle)
            {
                tmpAngle = ds.endAngle;
            }
            else{
                tmpAngle += ds.xAngle;
                tmpSum += ds.xAngle
            }
            // console.log(ds.startAngle+'***'+tmpAngle);
            // console.log(tmpSum);
            // ctx.clearRect(ds.x,ds.y,canvas.width,canvas.height);
            
            if(tmpSum > percent1 && tmpSum <percent2)
            {
                ctx.beginPath();
                ctx.moveTo(ds.r,ds.ry);
                ctx.arc(ds.r,ds.ry,ds.cr,ds.startAngle+percent1,tmpAngle);
            
                ctx.fillStyle = ds.p2;
            }
            else if(tmpSum > percent2 && tmpSum <percent3)
            {
                ctx.beginPath();
                ctx.moveTo(ds.r,ds.ry);
                ctx.arc(ds.r,ds.ry,ds.cr,ds.startAngle+percent2,tmpAngle);
                ctx.fillStyle = ds.p3;
            }
            else if(tmpSum > percent3 )
            {
                ctx.beginPath();
                ctx.moveTo(ds.r,ds.ry);
                ctx.arc(ds.r,ds.ry,ds.cr,ds.startAngle+percent3,tmpAngle);
                ctx.fillStyle = ds.p4;
            }
            else{
                ctx.beginPath();
                ctx.moveTo(ds.r,ds.ry);
                ctx.arc(ds.r,ds.ry,ds.cr,ds.startAngle,tmpAngle);
                ctx.fillStyle = ds.p1;
            }
            ctx.closePath();
            ctx.fill();
            requestAnimationFrame(drawCircle);
        }
        this.toDraw = function(){
            ds= defaultStyle(dom_circle,canvas);
            // console.log(tmpAngle);
            // console.log(ds.xAngle)
            ctx.clearRect(ds.x,ds.y,canvas.width,canvas.height);
            drawCircle();
        }
        this.toDraw();
        var self = this;
        window.onresize = function(){
            self.toDraw()
        }
    }

})(window);    
</script>
